Electric machines, for example electric motors, are used for a wide variety of purposes and applications in the automotive sector. By way of example, electric motors are used to drive radiator fan modules. Furthermore, electric motors are also used as drive for the operation of window lifters, belt pretensioners, seat adjusters, external mirrors, electric parking brakes, transmission actuators, oil pumps, for engaging the clutch and switching in a dual clutch transmission, and the like.
Electric motors of this type generally have a stator and a rotor which is rotatably mounted in the stator. The stator usually has a stator core which forms a multiplicity of stator teeth around which stator windings are wound in a known manner. The stator windings wound around the stator teeth generate an electromagnetic field when a current flows through the winding wire, which electromagnetic field, in cooperation with the rotor, causes the latter to rotate.
There are currently a multiplicity of options for connecting the stator windings to contact connections, which are then electrically connected to a connection bushing or an appropriate contact-making device. However, making contact with the winding wire of the stator winding to a multiplicity of individual contacts becomes very difficult and elaborate. The individual contacts must be fixed for this purpose in an insulating end plate or pocket before winding. During the winding process, for example by means of a needle winding or a flyer, a respective wire must be guided into a defined position close to or on the individual contacts in order to then electrically and mechanically connect them together. Furthermore, it is necessary now and then for a plurality of stator windings on the stator teeth to be connected to one another. This connection is usually made via the wire of the individual stator windings and therefore involves disadvantages of a complicated transfer from one stator tooth to an adjacent stator tooth to be connected.
US 2005 088049 A describes a stator for an electric motor which has an annular stator laminated core. An annular connection unit is provided on an end face of the stator core. The connection device has a support structure in which cutouts are formed. Electrically insulated connection rings, which connect individual stator teeth to one another, are provided in said cutouts.